Process of casting freely-oxidizable metals



UNITED STATES PATENT OFFICE.

HERMAN E. BAKKEN, OF NEW KENSINGTON, PIEITNSYLVANIA, ASSIGNOBTO ALUMI- NUM COMPANY. OF AMERICA, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF SYLVANIA.

PROCESS OF CASTING FBEELY-OXIDIZABLE METALS.

1,363,384.. No Drawing.

To all whom wit-may concern.

'a resident of New' Kensington, in the county I of Allegheny and State of Pennsylvania,

have invented a new and useful Improvement in Processes of Casting F reely-Oxidizable Metals, of which the following is a specification.

The object of the invention is to provide a process of making castings of freely oxidizable metals whereby the castings will not become oxidizedv during'the casting opera-' tion.

While the invention is adapted to the casting of various freely oxidizable metals, such as misch-metal and its constituents, cerium, lanthanum, didymium, etc., it finds particular applicability to the casting ofmagnesium, and will be so explained in the following description.

Attempts heretofore made to cast magnesium in ordinary molding sand have met with failure due to the fact that the magnesium, when so cast, catches fire and becomes wholly or partially oxidized. This peculiar behavior has been attributed to a reaction between the magnesium and thesan'd.

My invention is predicated upon my discoveries of the cause of such burning, and of how a clean sound magnesium casting can be made following ordinary foundry practices. I have discovered firstthat the burning or oxidization of the magnesium is due to the presence of water in the molding sand, the molten metal disassociating the water into its constituent elements and the thus freed oxygen combining with the magnesium; and secondly, that sound clean castings of magnesium can be made by freeing the molding sand of water and rendering it moldable by mixing it with a non-aqueous liquid.

In the practice of the invention, the molding sand may be dried in, any desired manner. It is then. mixed with sufficient nonaqueous liquid to give it the desired hys1- hile cal properties for molding urposes. various liquids may be used: such as animal, vegetable and mineral oils, I have found that a heavy petroleum hydro-carbon lubricating oil gives very satisfactory results. After the sand has been thoroughly mixed with and rendered moldable by the oil, a mold may be made in the usual way, and the mag- Specification of Letters Patent.

baked in the usual manner.

metal in'said mold. v

process of making a casting of Patented Dec. 28, 1920.

Application filed January 15, 1920. Serial No. 351,679.

nesium cast into it. The sand may be used to dry sand molding in which the molding sand, first freed from Water, is mixed with g a non-aqueous binder and then molded and As previously stated, the invention is applicable to the casting of freely oxidizable metals other than magnesium. I desire to have itclearly understood, also, that the invention is not limited to the casting of pure, or even substantially pure, freelyoxidizable metals, but that it is fully appli cable to alloys, such as aluminum-magne-' sium and ferro-cerium alloys, in which the freely-oxidizable metal constituent is 'pres-' ent in such proportions as will render the casting liable 'to destructive oxidization if made in a water-moistened sand mold. Ac-

cordingly, the freely-oxidizable metal contemplated in each of the appended claims includes pure metal as well as alloys thereof having oxidizing characteristics similar to the pure metal. I claim:

1. The process of making a casting of 5 freely oxidizable metal, which consists 111 forming a mold from sand freed from water and rendered moldable b being mixed with a non-aqueous liquid, an casting said metal in said mold.

2. The process of making a casting of freely oxidizable metal, which. consists in forming a green sand mold from sand freed from water and rendered moldable by bein mixed with a heavy oil, and casting sai 'freely'oxidizable metal, which consists in forming a green sand mold from sand freed from water and rendered moldable by' being mixed with a non-aqueous liquid, and casting said metal in said green sand mold.

4. The rocess of making a magnesium casting, w ich consists in forming a mold from sand freed from Water and rendered 10:

moldable by being mixed with a non-aqueous liquid, and casting molten magnesium in said mold.

5. The process of making a casting of a In testimony whereof I have hereunto set metal contaminga considerable proportion my hand.

, of magnesium which consists in forming a.

mold from said freed from water and ren- HERMAN BAKKEN' dered moldable by being mixed with a non- Witnesses: aqueous liquid, and casting the molten metal FRANCIS C. FRARY,

in the said mold. H. V. CHURCHILL. 

